e+e- yields in Pb+Au collisions at 158 AGeV/c: Assessment of baryonic contributions

Abstract

Using a hydrodynamic approach to describe Pb+Au collisions at 158 AGeV/c, we analyze e+e- yields from matter containing baryons in addition to mesons. We employ e+e- production rates from two independent calculations, which differ both in their input physics and in their absolute magnitudes, especially in the mass range where significant enhancements over expected backgrounds exist in the CERES data. Although the presence of baryons leads to significant enhancement of e+e- emission relative to that from mesons-only matter, the calculated results fall below the data in the range 400 < M_ee/MeV < 600, by a factor of 2-3. Since the calculated e+e- spectra are relatively insensitive to the equation of state for initial conditions that fit the observed hadronic spectra, either in-medium modifications of the e+e- sources more significant than so far considered, or the presence of hitherto unidentified additional sources of e+e- is indicated.

Revtex, 20 pages, 5 figures; submitted to Physics Letters B

References in corpus (7)

• Current correlation functions, QCD sum rules and vector mesons in baryonic matter
• Rho Meson Propagation and Dilepton Enhancement in Hot Hadronic Matter
• Low-mass e+e- pair production in 158 A GeV Pb-Au collisions at the CERN SPS, its dependence on multiplicity and transverse momentum
• The Spectral Function of the Rho Meson in Nuclear Matter
• P-Wave Polarization of the $\rho$-Meson and the Dilepton Spectrum in Dense Matter
• A Microscopic Calculation of Photoabsorption Cross Sections on Protons and Nuclei
• Initial Conditions in the One-Fluid Hydrodynamical Description of Ultrarelativistic Nuclear Collisions

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